Methods for joining more than two panels together and assemblies formed by the methods

ABSTRACT

An assembly for a vehicle and a method of making an assembly including more than three panels stacked together and joined by self-piercing rivets or by clinch joints. A first panel and a second panel are joined together at a first attachment point. A third panel and the first panel are joined together at a second attachment point. A fourth panel and the third panel are joined together at a third attachment point. The first, second and third attachment points are spaced apart to avoid interference between the self-piercing rivets or the clinch joints.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. application Ser. No. 14/105,995filed Dec. 13, 2013, now U.S. Pat. No. 9,249,816 B2 the disclosure ofwhich is hereby incorporated in its entirety by reference herein.

TECHNICAL FIELD

The present disclosure relates to several methods for joining more thantwo panels together and assemblies formed by the methods.

BACKGROUND

In automotive manufacturing, lightweight materials, such as aluminum,are used to produce fuel efficient vehicles. Sheet metal components arejoined together by welding or by using rivets, such as a self-piercingrivet tool 20 shown in FIGS. 1A-1D during a body-in-white stage invehicle manufacturing. Referring to FIG. 1A, a self-piercing rivet tool20 has a nose 22 that surrounds a punch 24. A rivet 26 is carried by thetool 20. The rivet 26 has a tubular body with a tapered end. In FIG. 1B,a self-piercing rivet 26 is shown engaging two panels 28 and 30. Thenose 22, punch 24, and rivet 26 are positioned on one side of the panels28 and 30, and a die 32 is positioned on the opposite side of the panels28 and 30. Referring to FIG. 1C, the punch 24 drives the rivet 26 intothe panels 28 and 30 until the rivet 26 penetrates through the panel 28into panel 30. The rivet 26 is flared to expand into the bottom panel 30and the rivet 26 forms a button on the bottom panel 30. Referring toFIG. 1D, the nose 22 and the punch 24 are retracted from the rivet 26. Ahead 34 of the rivet 26 is flush with the top surface of the top panel28.

The thickness and the number of panels to be joined by the rivet and thelength of the rivet may affect the strength of the interlock provided bythe rivet. Where more than two sheets of metal are joined, a rivet maynot flare sufficiently. This may result in achieving only a weakinterlock between the panels. Adhesives may be used with rivets toimprove the strength of the interlock between panels. However, adhesivesrequire time to cure and a weak rivet connection may allow the panels toshift positions before the adhesive cures. Riveting three or more panelstogether with a single rivet requires a longer rivet. The problem withlonger rivets is that they may break through the button in the bottomlayer. If the rivet joint is reinforced with adhesive, the adhesive maycontaminate the riveting equipment. Production downtime may be incurredfor cleaning the riveting equipment.

The above problems and other problems are addressed by this disclosureas summarized below.

SUMMARY

According to one aspect of this disclosure, a method is provided forattaching a plurality of panels together. The method comprisesassembling a first panel and a second panel together in a face-to-facerelationship and fastening the first panel and the second panel at afirst attachment point to form a sub-assembly. The method continues byassembling a third panel over the first panel covering the firstattachment point and fastening the third panel and the sub-assembly at asecond attachment point that is spaced from the first attachment point.

According to another aspect of this disclosure, the step of fasteningthe first panel and the second panel to form the sub-assembly mayfurther include inserting a first self-piercing rivet into the firstpanel in an area of the first panel that does not have a pre-drilled ahole. The self-piercing rivet may have a head that is driven into thefirst panel to be flush with a top surface of the first panel.

The step of fastening the third panel and the sub-assembly may includethe further step of inserting a second self-piercing rivet into thethird panel and the first panel at the second attachment point. Themethod may further include the step of assembling a fourth panel overthe third panel and inserting a third self-piercing rivet into thefourth panel and the third panel at a spaced location from the firstself-piercing rivet and the second self-piercing rivet. The rivetconnecting the fourth panel may be a longer rivet that is inserted intothree or more panels.

According to a further aspect of the method, the step of fastening thefirst panel and the second panel may include clinching the first panelto the second panel and the step of fastening the third panel and thesub-assembly may include clinching the third panel to the sub-assembly.

According to another aspect of the method of this disclosure, a methodis disclosed for assembling multiple parts. The method comprisesinserting a first plurality of rivets into a first flange and a secondflange in a first set of locations. A third flange is assembled over thefirst plurality of rivets in the first flange and a second plurality ofrivets is inserted into the third flange and the first flange withoutpenetrating the second flange in a second plurality of locations thatare spaced from the first set of locations.

The method may further comprise assembling a fourth flange over thesecond plurality of rivets in the third flange and inserting a thirdplurality of rivets into the fourth flange and the third flange withoutpenetrating the first flange. The rivets securing the fourth flange maybe inserted into three flanges. The second plurality of rivets haveheads that are flush with a top surface of the third flange.

According to an additional aspect of this disclosure, a method isdisclosed for assembling multiple parts. The method comprises the stepsof clinching a first flange and a second flange in a first set oflocations. Assembling a third flange over the first flange and clinchingthe third flange and the first flange in a second plurality of locationsthat are spaced from the first set of locations.

Other aspects of the method may further comprise the additional steps ofassembling a fourth flange over the third flange and clinching thefourth flange and the third flange in a third plurality of locationsthat are spaced from the second plurality of locations.

According to another aspect of this disclosure, an assembly is disclosedthat comprises at least three parts that are assembled withself-piercing rivets. The first part and the second part overlap in afirst overlap area. The third part overlaps the first part in a secondoverlap area. A first self-piercing rivet is inserted through the firstoverlap area to join the first and second parts. A second self-piercingrivet is inserted through the second overlap area to join the first andthird parts with the third part covering the first self-piercing rivet.

According to further aspects of the assembly, a fourth part may beprovided that overlaps the third part in a third overlap area. A thirdself-piercing rivet is inserted through the third overlap area to jointhe third and the fourth part. If the third self-piercing rivet islonger, it may be inserted through the first part in addition to thethird and fourth parts.

An alternative aspect of this disclosure relates to an assembly of threeor more parts that are joined together with a plurality of clinchjoints. A first part and a second part are assembled together to overlapin a first overlap area. A third part overlaps the first part in asecond overlap area. A first clinch joint is formed in the first overlaparea to join the first and second parts. A second clinch joint is formedin the second overlap area to join the first and third parts with thethird part covering the first clinch joint.

The assembly may further comprise a fourth part overlapping the thirdpart in a third overlap area. A third clinch joint may be formed in thethird overlap area to join the third and the fourth part. Alternatively,the third clinch joint may be formed in the third overlap area to jointhe third part and the fourth part to the first part.

The above aspects of this disclosure and other aspects are described ingreater detail below with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a cross-section view of two panels being joined by aself-piercing rivet.

FIG. 1B is the same cross-section view as FIG. 1A showing the punchinitially engaging the panels.

FIG. 1C is the same cross-section view as FIG. 1A showing the rivetbeing driven through the panels and flared.

FIG. 1D is the same cross-section view as FIG. 1A showing the nose andpunch being retracted from the rivet that secures the panels together.

FIG. 2 is a cross-section view of three panels joined together withseveral self-piercing rivets in accordance with one example of a methodof this disclosure.

FIG. 3 is a cross-section view of four panels joined together withseveral self-piercing rivets in accordance with another example of amethod of this disclosure.

FIG. 4 is a cross-section view of three panels joined together withseveral clinch joints in accordance with another example of a method ofthis disclosure.

DETAILED DESCRIPTION

The illustrated embodiments are disclosed with reference to thedrawings. However, it is to be understood that the disclosed embodimentsare intended to be merely examples that may be embodied in various andalternative forms. The figures are not necessarily to scale and somefeatures may be exaggerated or minimized to show details of particularcomponents. The specific structural and functional details disclosed arenot to be interpreted as limiting, but as a representative basis forteaching one skilled in the art how to practice the disclosed concepts.

Referring to FIG. 2, three metal panels 38, 40, and 42 are joinedtogether using several self-piercing rivets 44, 46, 48, and 50. Thesheets may be aluminum sheets and the assembly may be an assembly ofmixed metal types. The rivets are spaced apart from each other and areeach inserted into two adjacent sheets. First panel 38 and second panel40 are stacked together in a face-to-face relationship. The first panel38 is placed or stacked on top of the second panel 40. A firstself-piercing rivet 44 is driven through a first attachment point 52 onthe first panel 38 and into the second panel 40. The first attachmentpoint 52 is an area where the first panel 38 and the second panel 40overlap. The first panel 38 does not define a hole prior to beingpierced by the first self-piercing rivet 44. The first self-piercingrivet 44 has a head 54 that is flush with a top surface 59 of the firstpanel 38. The first panel 38 and the second panel 40 are joined by thefirst self-piercing rivet 44 to form a first sub-assembly 60.

A second self-piercing rivet 48 also connects the first panel 38 and thesecond panel 40. The second self-piercing rivet 48 pierces the firstpanel 38 at a second attachment point 56. The second attachment point 56is spaced from the first attachment point 52. The first panel 38 neednot define a hole prior to being pierced by the second self-piercingrivet 48. The second self-piercing rivet 48 has a head 58 that is flushwith the top surface 59 of the first panel 38. Additional self-piercingrivets may be used to join other areas of the first sub-assembly 60.

A third panel 42 is stacked in a face-to-face relationship with thefirst panel 38 of the first subassembly. The third panel 42 covers theheads 54 and 58 of the self-piercing rivets 44 and 48, respectively. Thethird panel 42, first panel 38, and second panel 40 are stackedtogether. A third self-piercing rivet 46 pierces the third panel 42 at athird attachment point 62. The third attachment point 62 is an area on asurface of the third panel 42 that does not define a hole prior to beingpierced by the third self-piercing rivet 46. The third attachment point62 is spaced from and not aligned with the first attachment point 52 andthe second attachment point 56. The third self-piercing rivet 46 has ahead 64 that is flush with the top surface 65 of the third panel 42. Thethird self-piercing rivet 46 pierces through the third panel 42 and thefirst panel 38 but does not pierce through the second panel 40.Additional panels may be attached to the assembly. For example, a fourthpanel may be assembled in like manner over the third panel.

A fourth self-piercing rivet 50 also pierces through the third panel 42at a fourth attachment point 66. The fourth attachment point 66 is anarea on a surface of the third panel 42 that does not define a holeprior to being pierced by the fourth self-piercing rivet 50. The fourthattachment point 66 is spaced from and not aligned with the firstattachment point 52, the second attachment point 56, and the thirdattachment point 62. The fourth self-piercing rivet 50 has a head 68that is flush with the top surface 65 of the third panel 42. The fourthself-piercing rivet 50 pierces through the third panel 42 and the firstpanel 38 but does not pierce through the second panel 40.

Referring to FIG. 3, another assembly 70 is shown that includes fourpanels 72, 74, 76, and 78 that are joined together by self-piercingrivets 80, 82, 84, and 86. Panel 72 is stacked in a face-to-facerelationship with panel 74. Panel 72 is attached to panel 74 using aself-piercing rivet 80 at attachment point 88 and another self-piercingrivet 82 at attachment point 90. Attachment points 88 and 90 are spacedapart from each other. Attachment points 88 and 90 do not define anyholes before being pierced with their respective self-piercing rivets.The self-piercing rivets 88 and 90 are pierced through panels 72.Self-piercing rivets 88 and 90 have heads, 92 and 94, respectively, thatare flush with a top surface 95 of panel 72 and their bodies, 96 and 98respectively, are flared within panel 74. Any number of self-piercingrivets may be used to join panels 72 and 74.

Panels 72 and 74 form a sub-assembly 100. Panel 76 is stacked on thesub-assembly 100 on one side of panel 72. The panels may compriseflanges of larger parts that are arranged in a face-to-facerelationship. Panels 76 and 78 are stacked together for assembly onpanel 72 of a sub-assembly 100 in a face-to-face relationship. Aself-piercing rivet 84 pierces through panels 78, 76, and 72 atattachment point 102. Another self-piercing rivet 86 pierces throughpanels 78, 76, and 72 at attachment point 104. Self-piercing rivets 86may be a longer rivet if it is to be inserted into three or more panels.While FIG. 3 shows the rivet 86 being inserted into three panels, it maybe inserted into two panels in a three panel assembly. Self-piercingrivets 80, 82, 84 and 86 join all four panels together. Attachmentpoints 102 and 104 are spaced from each other and are areas on panel 78that do not define holes prior to being pierced. The length of theself-piercing rivet depends upon the number, material and gauge of thepanels that are to be joined together. For example, self-piercing rivets84 and 86 pierce through two or three panels but not all four panels.The self-piercing rivets 84 and 86 combine with self-piercing rivets 80and 82 to join all four panels together.

Referring to FIG. 4, an assembly 112 similar to the three panel assemblyof FIG. 2 is shown. The panels in assembly 112 are joined by clinchinginstead of using self-piercing rivets to join the panels. Panel 106 isplaced or stacked on panel 108 in a face-to-face relationship. Panels106 and 108 are joined by clinching at a first overlap area 114 and at asecond overlap area 116. The first overlap area 114 is spaced from thesecond overlap area 116. The number of overlap areas that can beclinched to join panels 106 and 108 may be varied. Panels 106 and 108form a sub-assembly 118.

Panel 110 is placed on panel 106 of sub-assembly 118 in a face-to-facerelationship. Panel 110 and sub-assembly 118 are joined by clinchingthem at overlap areas 120 and 122. Overlap areas 114, 120, 116, and 122are spaced apart. Additional panels may be added to the assembly 112 andclinched at overlap areas that are spaced from other clinch joints.

The assemblies formed from the several methods described above includepanels that are interlocked by self-piercing rivets or clinch joints.The number of panels to be joined is not limited by the length of therivets or by the depth of the clinch joints. The assemblies and methodsof the present disclosure enable the assembly of three or more panelsefficiently with joints made by multiple self-piercing rivets ormultiple clinch joints. The assemblies and methods of the presentdisclosure may minimize or eliminate the problem of adhesivescontaminating the riveting equipment and causing assembly downtime.

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms of the disclosed apparatusand method. Rather, the words used in the specification are words ofdescription rather than limitation, and it is understood that variouschanges may be made without departing from the spirit and scope of thedisclosure as claimed. The features of various implementing embodimentsmay be combined to form further embodiments of the disclosed concepts.

What is claimed is:
 1. A method of attaching a plurality of panelstogether comprising: assembling a first panel and a second paneltogether in a face-to-face relationship; clinching the first panel andthe second panel at a first attachment point to form a sub-assembly;assembling a third panel over the first panel covering the firstattachment point; clinching the third panel and the sub-assembly at asecond attachment point that is spaced from the first attachment point.2. A method of assembling multiple parts comprising: clinching a firstflange and a second flange in a first set of locations; assembling athird flange over the first flange; and clinching the third flange andthe first flange in a second plurality of locations that are spaced fromthe first set of locations.
 3. The method of claim 2, furthercomprising: assembling a fourth flange over the third flange; andclinching the fourth flange and the third flange in a third plurality oflocations that are spaced from the second plurality of locations.
 4. Anassembly comprising: a first part; a second part overlapping the firstpart in a first overlap area; a third part overlapping the first part ina second overlap area; a first clinch joint formed in the first overlaparea to join the first and second parts; and a second clinch jointformed in the second overlap area to join the first and third parts withthe third part covering the first clinch joint.
 5. The assembly of claim4, further comprising: a fourth part overlapping the third part in athird overlap area; and a third clinch joint formed in the third overlaparea to join the third and the fourth part.
 6. The assembly of claim 5,wherein the third clinch joint formed in the third overlap area joinsthe third part and the fourth part to the first part.